Electric welding machine



Dec.- 4, l 1928. 1,.94,08l

w. si. REED ELECTRIC WELDING MACHINE c E l l\ Q Ln Jq XK O u] l 1 E I Gl: u @l L '"J"\ e e1 O Q r2 ,f o

Dec. 4, 1928. 1,694,081

W. E. REED ELECTRIC WELDING MACHINE Filed Aug. 13, 1924 10 Sheets-Sheet2 Dec. 4, 1928, 1,694,081

- W. E. REED f ELECTRIC WELDING MACHINE Filed Aug. 13, 1924 10Sheets-Sheet 5 INVENTOR Dec. 4, 1928. n 1,694,081

W. E. REED ELECTRIC WELDING MACHINE Filed Aug. 15, 1924 10 Sheets-Sheet4 INVENTOR Dec. 4, 1928. 1,694,081 w. E. REED ELECTRIC WELDING MACHINEFiled Aug. 13, 1924 10 Sheets-Sheet 5 n INVENTOR ELECTRIC WELDINGMACHINE Filed Aug. 13, 1924 lO SheSCS-Sheet 6 Dec. 4, 1928. 1,694,081

W. E. REED ELECTRIC WELDING MACHINE Filed Aug. 13, 1924 10 Sheets-Sheet7 INVENTOR may@ Dec. 4, 1928. 1,694,081 l w. E. REED ELECTRI C WELDINGMACHINE Filed Aug. 13, 1924 lO Sheets-Sheet 8 INVENTOR Jay I Dec. 4,1928. 1,694,081

W. E. REED ELECTRIC WELDING MACHINE 10 Sheets-Sheet 9 Filed Aug. 13,1924 INVENTOR l Shaw@ Dec. 4, 1928.y 1,694,081

W. E. REED ELECTRIC WELDING MACHINE Filed Aug. A13, 1,924 lOSheets-Sheet lO /45 E C a INVENTOH on an en arged scale; Figs. 11 and 12s ow s to 10;

Patented Dec. 4. 192s.

UNITED STATES, PATENT fol-"FICE,

WILLIAM EDGAR REED, OF PITTSB'Q'RGH, PENNSYLVANIA.

.f ELECTRIC WELDING MACHINE.

Application ined Ang-ust 13, 1924. semi No. 731,831.

My inventionrelates \to electric welding machines, and particularly tomachines for welding wire fabric and the like.

The invention constitutes an improvement over the type ofapparatusdescribed in my copending application for Letters Patent,

Serial No. 683,184, filed December(` 28, 1923,

now Patent No. 1,581,868.-

Some of the objects of my invention are, to provide an improved meansfor controlling the welding current; toprovide an improved means forfeeding the wires or rods going to make up the completed fabric; toprovide an improved means forsupporting and holding y the Wires 1nposltion; tov provide an improved form of support for the weldingelectrodes; to provide means for localizing the currents between theco-operating electrodes; toprovide means "for utilizing the weldingcurrent to assist in hol-ding'the wires in welding position; ytointermittently augment the welding pressures, and to simplify andimprove generally the struct-ure and operation of machines of thecharacter referred to.

Some of the forms which my invention may take are shown in the drawings,wherein Fig. 1 1 is a view, partially in section and partially in sideelevation, of a portion of a welding machine wherein certain features ofymy invention are included; Fig. 2 is an enlarged detail of a portion ofthe apparatus of Fig. 1 Fig. 3 is a view, in end elevation, of a portionof the apparatus of Figs. 1 and 2, but showing also a diagrammaticarrangement of the primary and secondary turns of' the weldingtransformer; Fig. 4 is a view showing a modiied form of swltch-closlngmechanlsm and control circuits for the transformer; Figs. 4;

vand 4J show modifications of the devices of Figs. 2 and 4; Fig. 5is aview similar-to that of Fig. 1, but showing an improved form of mountingfor the roller electrodes; Fig. 6 is a plan view of a portion. of theapparatus of' Fig. 5 ;Fig. `7 is a View of the portion of the apparatusof Fig. 5, on an enlarged scale;

Fig. 8 is a View, partially inside elevation and partially in section,of means for, supporting and locking the stay wires in position upon thecarrier; Figs. 9 and 10 ,are views of ortions of the apparatus of Fi."8,

modifications of the holding 'devices of Figs.

F 13 is a view taken on the line 1.3-13 of 1g. 11;-Fig.f14 shows amodified tially in section,

form, of the stay wire holding device; Fig'.

15 is a view, in perspective, of an improved arrangement of strand wireguide blocks and welding bars; Fig. 16 isa longitudinal sectional viewof a portion of the apparatus of AFig. 15; Fig. 17 is a view taken onthe line 17-17 of/Fig. 16; Fig. 18shows a modifica- .tion of the deviceof Fig. 16, taken on the line 18-18 of Fig. 19; Fig. 19 is a view, inend elevation, of the apparatus of Fig. 18; Fig. 20 is a furthermodication of .the device of Fig. 16; Fig. 21 is a schematicviewshowing' one manner in which the respective weldingv circuits may becontrolled; Fig. 2 2 is a view showing mechanism for applying increasedpressure to the electrodes; Fig. 23 is a modification of the apparatusofFig. 22; Fig. 24 is a view, on an enlarged scale, showing an improvedform of feeding device; Fig. 2,5\is a view showing one manner in whichwelds may be effected through roller electrodes mounted singly insteadof in pairs; Fig. 26 is a view,l partially in side elevation and par- Yofthe apparatus of Fig. 25; Fig. 27 is a modification of the device ofFig. 25; Fig. 28 is aview showing a modified form of contacter forcooperating with the roller electrodes to complete the circuit; Fig. 29is a view showing roller electrodes mounted i I nism, as well as avnumber of wel'dlng units A being some of the principal parts omitted. c'

The machine is adapted to weld fabric, which compriseslongitudinal orstrand wires 2 andtransverse or stay wires 3, the wires being fed infrom the right hand end of the.

machine shown vinFig. 1, and the finished fabric beingwithdrawn fromthe'machine at the left hand end thereof. The fabric is supported andcarried forwardbyV a conveyor chain 4 driven by sprocket' wheels `5 andcarryinganvil bars 6, upon which are mountproper welding pressure uponthe wires passing beneath the electrodes 10. Each of the Jframes 12carries av transformer 16 and a switch 17 tor controlling the flow ofcurrent through the primary coil 18 (Fig. 3) ot the transformer 16. 4

When the circuit through the primary coil 18 is closed, current iscaused to flow in the secondary circuit 19, the )ath of the currentbeing through the brushes 20, hub 21, ot one ot' the electrodes 10,through the wires 2 and 3 and the welding bar.7 tothe other electroderoller 10, its hub 22 and the brush 23.

It is desirable that current shall flow through the primary winding 18only for the very short period of time that is necessary to complete aweld, and that the circuit be broken automatically and that means beprovided for preventing the circuit remaining closed in the event thatthe machine should be stopped with the elect-rodes 10 in Weldingposition. In order to accomplish these objects, I provide the switch 17for controlling the primary vcircuit 2/1 of the transformer. In thecircuit 24 I provide a switch 25 that is normally held in closedposition by a spring 26, and which is controlled by an electro magnet 27having a coil connected in shunt relation tothe circuit 24.

The co-operating contacts of the switch 17 are so'positioned that theyare in yopen-ci'rcuit relation when the roller electrodes 10 are intheirlowermost position, between adjacent stay wires 3, but they aremoved into engagement when the rocker arms 12 and rollers 10 are raisedslightly upon passage of stay wires 3 therebeneath. Upon closure oftheswitch 17 current will flow through the circuit 24, thus causing a flowof welding current to be set up in the secondary coil 19. The

electro magnet or relay 27 is thereupon energized and moves the switch25 to open position, against the tension of the spring 26. The time ofoperation at this relay is adjustable. for adjusting the length of timethe welding current is applied. The switch 25 will be held open so longas the switch 17 remains closed. When a'stay wire 3 has been advancedfrom beneath the electrode 1() and the electrode 10 permitted to descendto the position shown in Fig. 2, the switch 17 is.

opened, de-energizing the circuit 24 and per- 'cross or longitudinalwires need not be Fig. et. lllhile the primary purpose ot thearrangement just described is to limit the period otl flow ot' thewelding current, it will be seen that should the chain l be stoppedwhile the electrodes are in welding position,

or be moved so slowly that it is desirable to interrupt the flow oi'welding current betere the stay wires have passed completely tronibeneath the roller electrode 10, the relay 27 will automatically openthe switch 25, thus cutting oil current from the electrodes.

In Fig. I have shown a pi'iiiiary circuit 21 and transformer windings 18and 19. 'Ihe circuit 24 is provided'with a switch 29 normally biased toopen position by a spring 30. Instead of controlling the switch 29directly by vertical movement of the electrodes, I provide a controlcircuit 31' which has a switch 32 normally biased to open position by aspringI 33 and having another switch 34 normally biased to closedposition by a spring 35. rThe circuit 31 is preferably D. C., while thecircuit 241 is, of course, A. C. In order to operate the switch 32 intimed relation to the movement of stay wires beneath the rollerelectrodes, as shown in Figs. 1 and 2, I provide cam'blocks 36 which areadjustable longitudinally of the chain 4c, to adjust time of applicationot welding current. The blocks may also be of varied length, to vary thelength ot time that welding current is applied. The roller 37 of a bellcrank 38 co-operates with the cam bloclr 36 to close the switch 32against the tension of the spring 33 at the instant that a stay wirepasses beneath the roller electrodes 10a which are at that timeelectrically associated with the circuit 24H.

`When it is desired to omit any welds or series of welds ot eitherlongitudinal or cross wires, certain of the (lugs that close the primarycircuit of the welding transformer may be removed from the table ordisplaced, or the cam -maybe displaced, so that it will not touch thelug as the table moves along, or the circuit 31 may be opened by aswitch, or certain fed into the machine.

The circuit 31 is provided for the purpose of energizing theelectromagnet 39 which closes the switch 29 against the tension of thespring 30 or gravity and completes the welding circuit 24a. In orderthat the welding circuit will not be maintained closed for an excessiveperiod of time, I p rovide a time limiting relay 40 connected in shuntrelation with the circuit 31, or any other known relay, for opening saidswitch after current has been lowing through the circuit 31 for apredetermined period of time. The switch 29, controlled by magnet 39,may be made to make l and break the Welding current by the continv nousmovement past adjustable contacts that vary the length of time theWelding current iiowsand thus eliminate the time relay. For instance,the stationary vided Withwide faces across which the movable contactslides in operation.

By providing a D. C. control circuit and operating magnet for the switch29, a quicker action of said switch is effectl than if the controlcircuit were A. C. Furthermore, the control circuit may be of relativelyloW voltage.

In Fig. 4a is shown a modification of the control circuits of Figs. 2and 4.v In this figure the 'Welding currentA for the transformerwindings 18c and 19c is supplied through acircuit 24". The circuit 24cis 36 into engagement With the rocker arm-38 that actuates the switch'17 to control the circuit 24. These bloc s are adjusted for time ofapplication and duration of flow of the 'Welding current. 'A D. C.auxiliary circuit,fan A. C. series lrelay* and a D. C. contactorL areprovided to control circuit 31c and for limiting the period oftime thatcurrent mayflow through the Welding circuit 24, independent of the camblocks and may ,operate before the circuit is opened by the cam blocks.y A

A magnet 40C is in seriesv with the circuit 24C, and when the switch 17cis closed the coil of 40c is energized to close the switch 34c tocomplete the control circuit 31. Thereupon the coil 39, ,in series withthe switch' 34 and the D. C lcircuit is energized and moves the switch29c to open position, thus breaking the Welding circuit 24C. TheWeldfing current is thus utilized to control the D. C. circuit which inturn controls the A. C. or Welding circuit. The D. C. or controlcircuitma' be of loW voltage. I provide an auxiliary holding coil40xthat is connected across the line 24c and which is of such resistanceand number of turns as to merely hold the switclc 34c A 31"will bemaintained, to hold the switch 29c open. Vhen the switch 17c is againopened, the line 24-c will be de-energized and the switches 34c and 29cbe permitted to return to their normal positionsas shown onthe drawings.y

Instead of employing a D. C. auxiliary control circuit such as 31c ofFig. 4, may provide suchauxiliary circuit in the form of a shunt circuit31d connected across the Welding circuit 24, as'shown in Fig. 4b. 'Acoil 40l is provided in series with the circuit ,.244

foractuating a switch -341to close the same upon energi'zation of thecircuit 24d. `A portion of the currentwill thereupon flow through thecircuit 31", energizing an A. Cj time limit and overload relay andcontactor' 39l to open a switch 29d and break tl Welding contacts can bepro-- closed, so that the circuit circuit 24d, and therefore interruptthe flow of current through the transformer coils 18d and 19d. Theswitch-29d willbe held open so long as the switch 17d is closed. Uponmovement of the Welding bars 7 to'open theswitch 17d, the switch 29dWill thereupon be' closed by a spring or gravity. Upon further movementof the Welding bars 7 the switch 17d Will be closed and the cycle /of'operation just described completed. Various other connections may beused and switch I l i 17c andthe opening of the-switch 29C. f primarilycontrolled by`movement of blocks Referring now to Figs. 5 to 7, I showan improved mounting for the roclring frames 12b which support theroller electrode 10b. While the rocking frames 12 of Fig. 1 are mountedfor pivotal movement in but one plane, and may have only a slightmovement in a plane disposed transversely of the path of travel of thechain, the rocking lframes 12b of F igs. 5 to 7 are mounted for pivotalmovement both in a plane parallel tothe path of travel of the chain 4and in a plane transverse thereto. I accomplish this by providing.transversely disposed pivots- '42 Which permit oscillation of the frame12b in a verti-A to uneven Wear of certain parts, etc.. so that/ each`roller will always make effective en ,gagement under pressure With theWires therebeneath. Instead of the double pivot mounting 42-43,so1peother universal movement as a ball and socket structure may be provided.

Referringto Figs. 8 to 10 inclusive. I have shown an improvedmanner offeeding and as Well as in my application above referred to, thestaywires aredeposited upon thebars 7 after the chain starts on itsupper horizontal flight. In order to permit the stay Wiresy Ato be sofed, the strand. Wires 2 must be fed atan angle, as shown in Fig. 1, andsuitable' guide means (not shown) provided therefor.

ino

vsupporting the Wires which are to be Welded.

-In the form of construction shown in Fig. 1,

ject,-I provide means 'whereby the stay Wires may be fed at a pointbelow the upper line of Ftravel of the chain 4. This necessitates .thechain, to permit ready e;- Le@ the provision of holding devices for thestay wires. Such holding devices are shown more clearly in l* lgs. 9 andl0, and comp-rise locking rods a5, which are normally pressed forwardlyby springs i6 so that when stay wires 3 are fed thereto,- as shown inFic: l0, sucli wires will be securely held in position upon the weldingbars T. The locking rods l5 are supported in brackets el? that aresecured to the anvil bars G and are provided with overhanging portions8, which, as shown in l0, bridge the gap between adjacent bars (i whenthe chain 1i is passing around the sprocket, thus preventing the wires 3from being accidentally deposited between opposing edges of the bars 6.rlie forward edge of each bar 6 may be provided with a plurality of noseportions el@ that fit in recesses of an adjacent bar, to supplement theoverhanging guards 4S and assist in preventing stay wires from fallingbetween the adjacent edges of the bars 6.

TWhen a bar 6 is advanced from the position shown in Fig. l0 to thatshown in Fig. 9, the over-hanging portions 4S serve to assist inretaining the said wires 3 in position. It will be understood that eachbar 6 is provided with a plurality of brackets 47, disposedlongitudinally of the bar, i. e., transversely of the carrier 4.

Fig. 9 represents a portion of the conveyor Il, adjacent to the lefthand or discharge end thereof, and shows means for disengaging the staywires 3 from the holding members. Each block or bracket 47 supports apivoted lever 52 which has a pin-and-slot connection with the lockingrod 45, so that when the lever 52 is moved in a clockwise direction, therod 45 will be retracted against compression of the spring 4:6, freeingthe stay wires 3 for withdrawal vertically from their seats on thewelding bars 7. In order to effect this withdrawal automaticallyI Iprovide, at a point adjacent to the left hand end of the conveyor 4;, aguide rail 53 with which the upper ends of the levers 52 contact and bywhich they are forced backwardly during forward travel of withdrawal ofthe fabric as indicated at the left hand end of Fig. 8.

Referring now to Figs'. l1 and 12, I have shown a modification of theholding devices of Figs. 8 to l0. Upon the blocks 55 which are carriedby the anvils 6, I mount springpressed slides 5G that normally projectover the nose portion 49a of the next succeeding bar 6, to prevent staywires being fed between adjacent edges of the bars 6. These slides 5G,when the chain 4 reaches the position shown in Fig. 1l, engage the staywires 3, to hold them firmly in welding position up'on their seats. Itwill be apparent that when the chain 4 reaches the left hand end of themachine, the flexure thereof will cause disengagement of the slide 56from the wire 3 and permit withdrawal of the mesh as shown in Fig. 8.

Referring now to le, I show a structure wherein the locking bars andslots of Figs. 8 to i3, inclusive, may be omitted for certain classes ofwork. In this form of construction a guide plate 58 engages the staywires 3 immediately after they are fed to the conveyor and maintainsthem in position while traveling around the breast of the wheel anduntil reaching a position on the roller, where thev will benuiintainedin place by gravity and by the strand wires (not shown) which are beingfed to the machine.

Villien welding, the desired path for the secondary welding current isfrom one transformer terminal through one rolling electrode. across onelongitudinal wire to the cross wire where the weld is made, then alongthe welding bar and through the cross wire again and anotherlongitudinal wire where a weld is made and then back through the otherrolling electrode to the other terminal of the transformer. Some of thecurrent may pass along the cross wire in a parallel path to the weldingbar between the two rolling electrodes without entering the welding bar,and some may pass through the welding table if the welding bar is notinsulated from it or the wires are in metallic contact with the table.Any current, whatever its path, however, is effective in making a weld,provided it passes between the cross and longitudinal wires at the pointwhere the weld is to be made. The path between the` rolling electrodesshould be low in resistance and inductance except the points where weldsare to be made.

There are some leakage or st 1ay paths which some of the welding currentmay follow, particularly when making some mesh products and small meshfencing, etc., instead of passing through the points to be welded, sothat these currents and the energy represented therein are not effectivein producing a weld, and diminish and vary the strength of the Weldingcurrent. For example, thepreceding weld offers a stray path from onehorizontal wire through the preceding weld, and preceding cross wire andthen back to the other electrode without passing through the points tobe welded. The same istrue to some extent with the wires to be weldedfollowing, although this leakage current must pass through pressurecontacts rather than welded contacts and therefore may not be soimportant. If the. cross orv longitudinal wires are in metallic contactwith metal guides or with the table, other stray paths are formed thatreduce the effectiveness of the welding current by short circuiting thepoints to be welded.

, In order to reduce stray currents and short circuits, as well as toutilize magnetic effects produced thereby, I provide the arrange- Mesos;

ments shown in Figs. to 20, inclusive. In Fig. 15 the Welding bars 7 aresupported by anvil bars 6 but insulated therefrom by any suitableinsulating material. The bars 6 are preferably of steel and the bars 7of` copper. Metallic guide blocks 60 of magnetizable material aresecured to but insulated from the anvil bars 6. These blocksfserve asguide- Ways for the longitudinalor strandwires 2. The strand wires 2 liewithin grooves formed in the blocks 60 which serve as magnets to` createa magnetic iield about the strand wires 2, as shown in Fig. 17 whencurrent tends to flow through them. This magnetic field resists flow ofcurrent longitudinally of the Jwires 2. This flow isundesirable, for thereasons above pointed out, for it will thus be seen that what wouldotherwise be a stray f current and wasted, is utilized to createinductive resistance to itsy own ow. x

In Figs. 8 and 17 I show a drag plate 107 of magnetizable materialpivotally supEorted to the rocker arm 12 and adapted to netic path forthe iuX. As each block reaches the drag plate, welding current will bepassing through the wires so that the platewill always be in position toact as a flux conducting member for the magnetic field shown in Fim-1 Inthe form shown in Fi s. 15` and 16, no provision is made for retar ingflow 'of current in the stay lwires 3, but in Fig. 18, lugs 61 and 62are provided at opposite sides of the stay wire 3,- the lug 61constituting, if desired, an extension of seating block 63. These lugs6l and 62 constitute a portion of the path of a magnetic field aroundthe stay wires 3 in a manner similar to the walls of the groo-ved blockand retard the iiow of current along the wire 3. It is generallydesir'able to omit these magnetic fields between .each of thek tworoller electrodes constituting a pair, in order to permit free flow ofcurrent therebetween, but, where used, the magnetizable fmembers, ifdisposed at opposite sides of each pair of electrodes, will tend toprevent stray airients flowing therepast along the stay wires 3.

The magnetic effects shown,in Figs.'17 and 18 may also be utilized toattract and hold the wires in position upon their seats.

As to Fig. 20, the magnetic reluctance cross wire is desirable where aminimum reridge. the side walls of the recessed block 60,'in theY mannershown in Fig'. 17, to complete a inagsistance to the flow ofcurrentfbetween'ladjae cent roller electrodes is desired. Fig. 21 showsa' schematic arrangement whereby the circuits of the various trans litwill be seen that if the switch 68 be closed,

the circuit therethrough will be completed, through brushes 73 andcommutators, 72, to

efl'ect a welding operation when wiresare passed beneath the electrodes10. The cornmutator isy provided with insulation 74 at predeterminedpoints on its periphery, so that the circuit 18a will be broken atpredetermined intervals to omit welding the stay wires to .the strandwires at certain points. The commutators 7l and 72 are driven throughconnections (not shown) in definite relation to the movement of thecarrier for the wires. The circuits 18b and 18c may, be similarlycontrolled, while the bank of electrodes represented in the circuits 18,18b and 18c may be controlled as a unit by the commutator 71,-tosimultaneously omit a serieslof welds.

For heavy wires, a greater pressure than that resulting from the weightof the rocker arm 12 and spring 15 of Fig. 1 is required,

and to secure such additional pressure I provide fluid pressure meanssuch as sh`ovvn in Figs. 22 and 23. In Fig. v2,2, the rocker arm 82 ispivotally supported and carries the roller electrodes 10b in a mannersimilar to the arm 12 of Fig. 1. However, above the outer end of the arm82 I provide acylinderA 83, inwhich a piston is operated by fluidpressure from a source 84,. the supply being controlled by a valve 85whichis normally spring-held in closed position. A magnet 86 controlsthe valvef85 and serves to open it against the pressure of its s ringwhen the magnet is energized upon closing of the welding circuit 87. Thewelding circuit 87 may be closed through the medium of a bell crank 98that is intermittently engaged by-guide blocks 99v to raise theswitch-operating rod 101, that actuates switches 102 and 103 forcontrolling the circuit 87 of the primary winding of the transformer, 1na manner s1m ilar to that described at length in my copelidingapplication above referred to..` f

When the circuit 87 is closed to effect a welding operation, the magnet86`will thereupon be energized and the valve 85 opened, thus admittingHuid under pressure to the cylinder 83, and forcing the outer end of thearm 82 downwardly, thus increasing pressure at the welding point.

rEhe rod 101 remains in elevated position only momentarily, and as itdescends the switches 102 and 103 are opened, thus breaking the circuit87 and cle-energizing the coil 86, thereby permitting the valve 85 to beclosed by its spring and cut off the supply of pressure fluid. 4

En Fig. 23 l' have shown a modification of the 'apparatus of Fig. 22. lnthis ligure the transformer circuit is the same as in Fig. 22, but thecircuit for actuating the magnet- 863 is independent of the weldingcircuit and is controlled directly by the elevation of the rod 101, bymeans of a vertically adjusted switch 104. The additionalpressurethrough the valve 85a may thus be timed without regard to theclosing of the welding circuit, thus the additional pressure may beapplied either in anticipation of or directly after the closing of thewelding circuit. lt may be desired to open the valve in advance of the.closure of the weldingcircuit, to permit accumulation of pressure inthe cylinder previous to closure of the welding circuit, so that a`welding blow will be delivered in proper relation to the heating of thewires.

lllelding current can be supplied from the saine source as that employedto drive the motor which operates the table, in which case such currentwill be automatically out od upon cutting od of the supply to the motor.

Both heat and pressure are required to produce said welds. Fressure, ifany, at the time of application of the Welding current to heat thewires, must be very light, or suicient resistance will not be providedto the flow of the current. it is therefore advisable to complete thewelding circuit immediately before the application of pressure, whichapplication may occur both-by movement of the stay wire and its seatingblocks into lposition beneath the roller electrodes, producing a hammerblow effect and bythe application of fluid pressure and the like tosupplement the weight of the rocker arm 12 and the spring mounted at theupper end thereof. The weight of the arm 12 may be varied as by weightsadjustably mounted thereon.

The piston in Fig. 22 is returned to retracted position by elevation ofthe outer end of the arm 82- and the valve 85 may be provided with ableed port to permit exhaust from the cylinder 83 during retraction ofthe piston. The magnetizable members of Figs. 15 to 20 may be suppliedwith current from a source extraneous to the Welding current, and may beprovided with magnetic coils, if desired. 5

1n Fig. 4 1 have shown anti-friction rollers 106 which may be disposedbelow the anvil bars 6 atpoints where they pass beneath the rollerelectrodes. These rollers serve to re- -spring 121.

Learner lieve the friction at points where welding pressure is applied.

In Fig. 24 I have shown an improved forni of feeding apparatus wherebythe stay wires are fed one by one, in timed relation to the movement ofthe conveyor 4, so that a wire is delivered each time to the conveyor atthe instant that certain of the bars 6 reaches receiving position, asshown in the drawing.

The device 'comprises a rocker arm 110 that is oscillated in timedrelation to the movement of the conveyor. The rocker arm is pivotallysupported at 111 and is provided with'a longitudinaly movable plunger112, that is normally pressed upward by a spring 113, and is providedwith a latching recess 114. The arm 110 is shown in wire-receivingposition. From this position it is moved forward by mechanism, notshown, to the position indicated in dotted lines. The stay wire isguided out of engagement with the arm, by means of a curved plate 115,into its seat upon the anvil bar 6. During this forward movement a cam116 engages a roller 117 carried by the plunger-112, drawing it downlagainst the 'compression of the spring 113 and causing it to be engagedby a latch 119 that locks it in retracted position.

The latch 119 is pivotally connected to the lower end of a pivoted lever120 that is normally biased in a clockwise direction by a There are aplurality of rocker arms provided for engaging the wires 3 at differentpoints longitudinaly of the wires. rhese arms may be arranged in two ormore sets, so that one set may be advancing a stay wire while anotherset is picking up a wire to be advanced, to effect amore rapid feed.

Upon return movement of the rocker arm 110 with the plunger 112 lockedin retracted position, as described, the pivoted lever 120 is engaged bythe leading stay wire 3, causing4 it to be rocked in a counter clockwisedirection and to disengage the latch 119 from the plunger 112, andpermitting the plunger to be forced upwardly to the position shown inthe drawing. The a-rm'110 is then ready to feed another -wire to themachine.

The wires 3 may be advanced in timed relation to the movement of therocker arm 110 and the conveyor 4, or may be fed against a yielding stop(not shown) mounted adjacent to the retracted position ofthe rocker arm110, so that a stay wire will always be in position to be picked offbythe plunger 112 and the lever 120. The lever 120 acts as a feeler andis provided with an adjustable stopscrew 1203, to permit adjustmenttowires of vavrious thickness. 'This adjustment may be obtained in otherways, as by changing thelatch 119, or by making the arm jointed, etc.,to in-v sure the applicability of the device to wires of g differentthickness.

The carriers composed of the arms and the members 112 and 120 willall'eiectively engage each wire to carry it forward in substantialparallelism with the welding bars,

- regardless of irregularities in the wire or misalignment thereof whenbeing picked up.

Referring now to Figs. and 26, I show a manner in Which single welds oran odd `number of welds may b'e readily made, as referred to in my saidapplication for patent,

` roller electrode 125 is carried by the shaft 130 and also a contactroller 131, both insulated by' insulating bushing from the shaft 130, asindicated in Fig. 26. The electrodes and the roller 131 may be connectedto a transformer 132 in'themanner shown in Fig. 32. In this arrangementthe contact roller 131 actsas an idler and serves merely to complete thecircuit through the secondary coil of the transformer and t-he rollerelectrodes. The rollers 125 and 131 are each connected to thetransformer 132 through a flexible conductor 133.. y

By the arrangement `just described, t-he pressure on each electrode maybe independently adjusted and .uniform welding therefore obtained. Wherethe elec-trodes are jterial beneath therespective electrodes of a pairat a given time. Y

In order that no more than the necessary pressure shall befappliedthrough the contact rollers 131, I may mount `such roller loosely uponthe axle andv hold it centralized thereon by means of springs 135 inostead of the usual rigid sprockets.

In Fig. 27 still another manner of yield* ingly mounting` the Contactroller 131u is shown. In this form of device the contact roller and theroller electrode are mounted on independent shaft-s and the shaft forthe roller electrodes is supported by a telescopic hanger member 136normally pressed downwardly'by a spring 137 which is under ten- -sionnearly sufficient to insure proper electrical contact between the roller131a and a contacting bar 138 which is disposed longicutout portions toaccommodate the stay Wires 3, so that a substantially smooth path willbe provided for the members 131' and 131A.

' In Fig-28 I shovsT a yielding contact member 139 which may be`employed in lieu of the roller contacts 131, for completing the circuitthrough the roller electrodes 125. The member 139 is of flexibleconducting ma# terial, the arms ofbwhich are normally biased apart bysprings 140 to effect engagement between the brush member 141 and theconductor bar 138a carried by the table. f

In Fig. 29l I have shown a pair of rollerl electrodes 142 mounted,similarly to the electrodes 125, and also'capable of independentpressure adjustment, but having a common return conductor '143 in' lieuof the roller conductors 131 'of Fig. 25. This return conductor consistsof a brush 143, normally biased downwardly by a spring 144, and engagingthe conductor bar 145 on the Welding table. The brush may be connectedto the transformer132aL through flexible connectors (not shown). Theroller electrodes 142 are connectedin parallel, as shown inv Fig. 30, Byemploying a single transformer for a plurality of electrodes, it ispossible to sef cure closer spacing of the strand wires.

Still another manner of connecting the roller electrodes 142 and thecommon return conductor 143, as shown in Fig. 31, wherein the commonreturn may be employed even though a transformer is provided for eachelectrode.

I claim as my invention:

1. Electric wel-ding apparatus comprising a rotatable elect-rode, arectilinearly movable electrode cooperatingtherewith, means forpermitting movements of one of said electrodes toward and away from theother electrode, a welding circuit, and means actuated bythe last namedmovement of said one elec' trode for closing saidcircuit.

2. Electric welding apparatus comprising cooperating electrodes one ofwhich is movable with respect to the other, a welding lcircuit, a switchin said circuit closed/and opened by successive movements of saidmovable electrode, and a time element device adapted to1- be energizeduponclosure of the welding circuit for interrupting said weldingcircuit,

' the said device being de-energiz'ed upon the opening of the saidswitch.

3. Electric weldingv apparatus comprising relativelyy movableelectrodes, a welding circuit, means actuated by successive movementsof-one .of said electrodes relatively to thel other, for closing andopening said circuit, l

and means' energized upon closure of said circuit for interrupting thesame, the last' named means being de-energized upon opening of theWelding circuit, 4. Welding apparatus comprising a movable electrode, apair of laterally spaced co-l i operating electrodes,and means forsupporting said electrodes for movement about van axis parallel to theline of movement ofksaid.

first-named electrode.

5.Welding apparatus comprising a mev able electrode, a pair of laterallyspaced coon said carrier for engaging one side or" the material, acooperating electrode engaging the other side of the material, a weldingcircuit controlled by movement of the carrier, an auxiliary circuitenergized upon closure of the welding circuit, and a pressure devicecontrolled by said auxiliary circuit, for exerting welding pressure onone of said electrodes. y

22. Electric Welding apparatus comprising a carrier for material to bewelded, electrodes on said carrier for engaging one side 'of thematerial, a cooperating electrode engaging the other side of thematerial, a welding circuit controlled by movement of thecarrier, anauxiliary circuit energized upon closure of the welding circuit, and apressure device controlled by said auxiliary circuit, for exertingwelding pressure on one of said electrodes, the 'auxiliary circuit beingclosed in predetermined relation to the movement of thek carrier. y

23. Electric welding apparatus comprising co-operating electrodes, meansfor pivotally supporting one -ofsaid electrodes for movement withrelation to the other electrode, a carrier for the material to bewelded,

a welding circuit, a switch in said circuit controlled by pivotalmovements of the movable elect-rode, and means operating inpredetermined relation to the movement of the carrier, for moving thelast named electrode to actuate said switch.

24. Electrical welding apparatus comprising co-operating electrodes; oneof which Iis -movable with respect to the other; a carrierl for one ofthe electrodes and for the material is movable with respect to theother; a cary rier for one of the electrodes and for the material to bewelded, a welding circuit, a control'circuit, means actuated by movementof said carrier for closing one of said circuits and for effectingclosure of the other circuit 'upon the closure of the said one circuit,and

a time element device in the cont-rol circuit for breaking the weldingcircuit.

26. Electrical welding apparatus comprising co-operating electrodes, oneof which is movable with respect to the other, a carrier for one of theelectrodes and for the material to be welded, a weldin circuit, acontrol circuit, lmeans actuate by movement of said carrier for closingone of said circuits and for effecting closure of the other circuit uponthe closure of the said one circuit, a

time element device in the control circuit forV breaking the weldingcircuit, and means for restoring the initial condition of said circuitsupon further movement of the carrier.

In testimony whereof I, the said VVILLlAM EDGAR REED, have hereunto setmy hand.

WILLIAM EDGAR REED.v

